My wife's Suzuki Jimny had a new catalytic converter/exhaust fitted by a main dealer in February 2012. She was charged £600.00 plus VAT. In November, the system failed and a local garage replaced the system with a similar system at a cost of just over £200.00.

They did not contact me prior to replacing the system as they thought the faulty unit was the original. I have now been told that Suzuki will only refund the trade cost of the first replacement which will be approximately £335.00 in total. What are my wife's rights under the Consumer Protection Act 1987?